It is well known that a light beam can be varied in intensity to produce a signal containing information within the amplitude modulation. Furthermore, telecommunications systems rely upon modulating the wavelengths of the light signals in fiber optics, to impart data onto the light beam. Furthermore, it has been shown that a fluorescent light source can be used as a one-way communications device (Dachs, U.S. Pat. No. 3,900,404, Aug. 19, 1975) for voice communications using an external modulated signal imparted upon the lamp's AC current in an amplitude modulation scheme.
The inherent weakness in this system (Dachs) is the fact that the observed light flickers as a function of the audio signal's intensity. For many applications, this is an unacceptable solution. Subsequent publications and inventions have conceived different modulation techniques such as pulse code modulation and timing modulation and have adapted the encoding techniques for applications that require greater data bandwidths with mixed data types (Leeb, et al, U.S. Pat. No. 6,794,831, Sep. 21, 2004); however, these designs are complex and require a greater amount of power, circuitry, and cost to accomplish.
Through applied effort, ingenuity, and innovation, Applicant has identified a number of deficiencies and problems with visible light modulation and demodulation systems. Applicant has developed a solution that is embodied by the present invention, which is described in detail below.